An object of the present invention is a method to measure the molecular diffusion and/or perfusion parameters of live tissue. To this end, the tissue is subjected to nuclear magnetic resonance (NMR) experiment. The invention can be applied, more especially, to the field of medicine where experiment of this type is undertaken in diagnosis involving human patients. It can, of course, also be used for animals. It is more especially applied in association with methods for the imaging of the parameter measured. The chief parameters measured are the constant of molecular diffusion and/or the percentage of capillaries perfused, and the measurements are performed chiefly on the brain.